The circuit uses five RF transistors with a cut-off frequency of at least 600 MHz. The PCB is designed for the (S)S9018 transistors (EBC pinout), but you can use any kind of low power RF NPN transistors, even the old types like BF200 or BF214 (pay attention to pinout).
The amplifier's input is unbalanced and it can be connected to any kind of antenna (after the balun if it is necessary). Because Q5 is placed in a common base configuration, the input impedance is high, thus the amplifier can be used with whip antennas too (they usually have high impedance at low frequencies). The output is 75 ohms unbalanced. The overall gain of this amplifier is 20 dB.
Here is the schematic of the amplifier. All capacitors are ceramic disc type. L1 RF choke can be omitted if you want to power the amplifier from a separate power supply.
|Gain is 20dB|
Based on an article from Romanian electronics magazine "Tehnium".